num1 = int(input('请输入一个100-999的三位自然数：'))
bit1 = num1%10
ten1 = (num1//10)%10
hund1 = num1//100
num2 = (bit1*10 + ten1)*10 + hund1
print('这个自然数的倒序输出为：', num2, sep = '')